The present invention relates to a semiconductor device, for example, to a semiconductor device using a nitride semiconductor.
In recent years, attention has been paid to a semiconductor device which is made of compounds of Group III-V having a band gap larger than that of silicon (Si). Among them, an MISFET made of gallium nitride is advantageous in that (1) a breakdown electric field is large, (2) an electron saturation velocity is high, (3) a thermal conductivity is high, (4) an excellent heterojunction can be formed between AlGaN and GaN, and (5) gallium nitride is a material that is non-toxic and high in safety.
For example, Japanese Unexamined Patent Application Publication No. 2009-9993 discloses a semiconductor device in which an HFET having an AlGaN/GaN heterojunction structure is arranged on a silicon pin diode.
Also, Japanese Unexamined Patent Application Publication No. 2010-40814 discloses a semiconductor device in which a pn diode is coupled between a source electrode and a drain electrode of the GaN-HFET.